CORE TITLE: Targeting Core CORE SUMMARY: Traditionally, robust protein-specific targeting ligand requirements are met by antibodies (Abs). Antibodies however often have significant problems, including high cost, selection difficulties, selectivity problems, preparation difficulties, stability and immunogenicity. The Targeting Core objective is to provide the Projects in the TCCN sets of targeting reagents for the nanoparticles that not only includes "gold standard" antibodies but novel aptamers and peptides to both endothelial, cancer and stem cells, both to specific cell surface ligands as well as the cells themselves. All projects will use the resources from the Biological Targeting Core. Specifically, the Targeting Core will develop thioaptamers and next-generation Xaptamers for targeting nanoparticles to CD44 (Project 1;Aim 2), E-Selectin, (Project 1: Aim 2, Project 2: Aim 2), VGFR, EGFR, ICAM-1 and cells (Project 3: Aim 1) and peptides and antibodies via phage display for targeting proteins (Project 1;Aim 2) and cells (Project 3: Aim 1;Project 4: Aim 2). Additionally, the Targeting Core will provide conjugation of targeting ligands and all micro/nanoparticles (Projects 1-3).